Soaking pit



July 2, 1929. H. c. RYDlN-G 1.519.452

SOAKING PIT Filed March 3, 1927 3 Sheets-Sheet l July 2, 1929. C, RYDlNG1,719,452

SOAKING PIT Filed March 3, 1927 3 Sheets-Sheet 2 j?? 062e for @wwwPatented July 2, 1929.

UNITED STATES HERBERT C. RYDING, OF BIRMINGHAM, ALABAMA.

SOAXING PIT.

Application led March 3, 1927. Serial No. 172,387.

The present invention is related to the invention disclosed in myco-pending application Serial No. 102.443, filed April 16, 1926. Theembodiment of the invention described and illustrated in my formerapplication included a recuperator for pre-heating the air used tosupport combustion. The invention is not limited, however, to the use ofsuch a recuperator. The embodiment of the invention illustrated in thepresent application is in many respects similaito the apparatusillustrated in my former application, a chief distinction being that inthe present case the recuperator is omitted.

Heretofore, it has been practically universal practice to providesoaking pits with checkerwork or regenerative chambers for preheatingthe air used to support-combustion in the soaking pit and it hassometimes been the practice to also preheat the gas used as fuel. Theprior practice has been to periodically reverse the direction of travelof the fuel and waste gases. Therefore, the prior types of soaking pitsrequired usually two sets of regenerative or so-called checker chambers'and various forms of reversing valves and conduits for reversing thedirection of travel of the fuel and waste gases to and from the soakingpit. My invention eliminates the necessity of installing regenerativechambers such as previously used and does away with reversing valves andother necessary operating gear. The economies eiected by myconstruction, conservatively estimated amounts to about one-third of thecost of prior constructions.

The invention will be apparent from the following specification whenread in connection with the accompanying drawings and the features ofnovelty will be pointed out with particularity in the appended claims.In the drawings- Figure 1 is a plan view with parts shown in section ofa four hole soaking pit embodying m invention, the view being intwoparts ivided on the lines a-a.

Figure 2 is a longitudinal section on line 2-2 of Figure 1, this viewbeing in two parts divided on lines [1 -b.

Figure 3 is a transverse section on line 3-3 of Figure 1.

Figure 4 is a section on the staggered line 4 4 of Figure 1.

Referring in detail to the drawings, the soakin pit includes end walls10 and 12 and si e walls 14 and 16 and division walls 18, 20 and 22,which divide the structure in such way as to form what is termed in theart a four hole soaking pit.

The four holes thus formed are numbered 1 to 4 inclusive, in Figure 1.Each hole is adapted to receive one or more ingots to be reheated aswill be hereinafter more fully described. The several holes or pits areof the same construction and arrangement and are provided with thesimilar devices for supplying gas and air to opposite sides thereof;hence, a description of one will suce for all. 4Each pit is open at thetop and a removable cover or roof 24 is supported b a suitable carriage26 having wheels 28 Whlch are arranged to travel on tracks 30 formingpart of a suitable super-structure 32.

Each hole or section of the soaking pit includes an ingot chamber 34adapted to receive the ingots 36 which are to be reheated for thepurpose of properly conditioning them for subsequent rolling.

The structure of refractory material is so arranged that flame chambers38 and 40 open into each ingot chamber 34.

The lower walls 42 of said flame chambers are preferably inclined sothat they serve as a baile against which the llames from burners 44strike. It is important that the flame chambers 38 and 40 be ofconsiderable length so as to prevent burning the ingot. I havediscovered that when using direct gas fired burners in which the air andgas is preheated outside of the soakin pit, as hereinafter described,that the lengt i of the flame chambers must be in excess of two feet asmeasured in a line from the end of the burner to the nearest wall of theingot chamber 34, that is to say the distance indi# cated by thedimension line X in Fig. 3 must be two feet or over. The upper wall orroof 46 of each flame chamber is preferably, though not necessarilytapered upwardly as shown.

In the embodiment of the invention illustrat-ed the ingot chambers areheated by an explosive fuel formed of a mixture of coke oven gas andair, which is mixed in the inspirator portions 48 of the burners, whichit is noted are located wholly outside of the refractory structure ofthe soaking pit. Coke oven gas is supplied to the several burners from agas manifold 50 having branches 52 and 54 leading to the burners on theopposite side of the pit. Air is supplied to the burners under pressureby means of a blower 56 connecting with an air manifold 58 havingbranches 6() and 62 leading to the burners on the opposite side of thesoaking pit. Because of the fact that the air is supplied under pressureit serves to draw the gas from the gas supply pipes and thoroughly mixit in the inspirator chamber 48, so as to form thorough explosivemixture which ignites instantly and burns with great rapidity within theflame chambers 42. Very low pressure of gas is required as the airpressure will inject suflicient gas when the pressure in the gasmanifold amounts to only one or two inches of Water. Valves 53 and 61control the supply of gas and air to the burners 44.

Located in the opposite walls of the ingot chamber at a point midwaybetween the flame chambers, I provide waste gas outlet ports 64 and 66,which open into flues 68 and leading to tunnel flues 72 which connectwith an outlet or stack 7 4. The bottom surfaces of the outlet ports 64and 66 are on an incline as indicated at 67 so as to prevent theaccumulation of dust or other foreign matter thereon. The flues 72 areprovided with suitable flue dampers 76 and ghe -stack is provided with asimilar damper A suitable cinder bed 80 is formed on the bottom wall 82of each ingot chamber. A clean-out opening 84 in the bottom wall isprovided with a breakable plug 86 which may be knocked out for thepurpose of cleaning out the pit at desired intervals. A tunnel 88extends longitudinally below the several holes of the soaking pit andprovides for the entrance of workmen to clean away refuse dischargedthrough the clean-out holes 84.

In operation the in'gots to be treated are lowered into the pit or ingotchamber by the usual form of overhead tackle suspended from a travelingcrane. The roof or cover 24 is moved to the position shown in Figure 3.The ingots are then subjected to the heat from the oppositely disposedburners 44 which simultaneously direct the flame in the direction of theingots. The flames strike the refractory walls of the flame chamberswhich are designed to absorb and reflect the radiant heat uniformlythroughout the entire length of the ingot. The waste gases from bothflame chambers simultaneously are ejected or exhausted through theoutlet ports 64 and 66 in the opposite walls in the center of the ingotchamber. These outlet ports are of relatively restricted area. Becauseof this restricted area and also because of the fact the explosivemixture of fuel is supplied under pressure, a super-atmospheric pressureis maintained in the ingot chamber. The amount of air mixed with the gasoutside of the pit is proportioned to effect complete combustion withinthe flame chambers.

cause of this complete combustion and because of the fact that apressure is maintained inthe ingot chamber, it is apparent that free airor oxygen is excluded from the ingot chamber. This enables me tocontinuously maintain either a neutral or a reducing atmosphere in theingot chamber. By maintaining such a reducing or neutral atmosphere inthe soaking pit, I am enabled to prevent oxidation or formation of scaleon the outside of the ingots. Heretofore such cinder scale losses haveamounted to approximately 21/2% to 3%. By my improved method these scalelosses will be materially reduced and will amount to not more than 1%.This saving alone in oxidation of ingots will practically pay for thecost of the fuel required to heat the steel in preparation for rolling.

In the old form of soaking pit heretofore used which employedregenerative chambers for preheating combustion air, it was necessary toreverse the direction of the flow of the fuel at regularly statedintervals. Skilled operators were required to operate such pits, thetime for reversal of flow of fuel being practically determined by the oerators skill in judging the temperature o the pit by the color of theflame escaping from sight holes in the roof of the pit. If reversal werenot made at the proper time, the ingotsl were improperly heated formingcold spots and sometimes even burned. The temperature of the checkerchambers were frequently unbalanced by reversal of flow at impropertimes. All of this has tended to make the operation of heating ingots byformer methods very inefiicient. My improved soaking pit employs directgas fired burners and there is no reversal of flow of fuel required. Thedesign and arrangement of the pit is such that ingots cannot help but beuniformly heated throughout. My improved pit can be operated byrelatively unskilled labor. The inclined bottom walls of the flame ehambers of my improved pit are of such inclina tion and length that saidwalls function to deflect and break the force of the flame. Thisprevents direct impingement of the flame against the ingot. The ingotmay be said to be bathed uniformly throughout its entire surface byradiant heat, in a neutral or non-oxidizing atmosphere.

Though I have described quite specificallyv the embodiment of theinvention herein illustrated. it is not to be construed that I amlimited thereto since various changes may be made by those skilled inthe art without departure from the invention as defined in the appendedclaims.

What I claim is 1. In the heating of ingots to prepare them for rolling,the method which consists in placing them in a pit and supplying exxplosive gaseous fuel to the pit so as to 130 maintain therein a pressureabove atmosphere and thus exclude air from the pit which would oxidizethe surface of the inotf.

2. In the treatment of ingots, the method which consists insimultaneously directing explosive gaseous fuel toward opposite sides ofthe ingot and withdrawing the waste gases from a point substantiallymidway between the points at which the fuel is introduced so as touniformly heat the ingot, and maintaining a pressure above that ofatmosphere while heating the ingots.

3. A soaking pit comprising a structure of refractory material having achamber formed therein adapted to receive an ingot, means located whollyoutside the pit structure for mixing fuel and air, means for dischargingthe explosive mixture thus formed into said chamber and an outlet portof restricted area adapted to assist in maintaining a pressure in saidchamber above that of atmosphere. f y

4. A soaking pit comprising a structure of refractory material having achamber formed therein adapted to receive an ingot, means locatedoutside said structure for mixing fuel and air and discharging saidmixture under pressure into said chamber so as to prevent entrance ofany free air into the chamber, and outlet ports for the waste gases. f

5. 'A soaking pit comprising a structure of refractory material having asubstantially rectangulai` chamber formed therein adapted to receive aningot, separate means located outside said structure on opposite sidesof said chamber for mixing fuel and air, means for simultaneouslydischarging said mixtures at o posite sides of the pit, and outlet portsormed in the walls of said chamber at right angles to the walls throughwhich the fuel is introduced.

6. A soaking pit for heating ingots comprising a' structure ofrefractory material having a substantially rectangular ingot chamberformed therein, flame chambers opening into the opposite ends of saidingot chamber and having outwardly converging top and bottom walls,burners located outside of said structure, means for Supplying `gas andair to said burners arranged to deliver an explosive mixture underpressure to said flame chambers and outlet ports formed in the sidewalls of said ingot chamber at right angles to said end walls.

7. A soaking pit for heating ingots comprising a structure of refractorymaterial having a substantially rectangular ingot chamber formedtherein, flame chambers opening into the opposite ends of said ingotchamber, the bottom wall of said flame chamber being inclined downwardlytoward said 'ingot chamber, burners outside said structure for supplyingan explosive fuel mixture under pressure to said flame chambers andoutlet ports located' in opposite Walls of said ingot chamber at pointsmidway between said flame chambers.

8. A soaking pit for heating ingots comprising a structure of refractorymaterial having an ingot chamber formed therein, in combination withflame chambers opening into the opposite ends of said ingot chamber,burners for discharging a fuel mixture to said flame chambers, thelength of each said flame chambers being greater than two feet inlength, measured from the outlet of the corresponding burner to thenearest wall of the ingot chamber.

9. A soaking pit for heating ingots comprising a structure of refractorymaterial aving an ingot chamber formed therein, in

combination with flame chambers opening into the opposite ends of saidingot chamber, burners supplying a fuel mixture to said flame chambers,and outlet ports formed in the opposite walls of the ingot chamber atright angles to said ame chambers, said ports being at an elevationabove the floor of said ingot chamber and thebottom surfaces of saidports sloping downward to# ward said ingot chamber t0 preventaccumulation of soot or scale thereon.

l0. A soaking pit for heating ingots comprising a structure ofrefractory materials having a substantially rectangular ingot chamberformed therein, flame chambers opening into the opposite ends ofsaidingot chamber and having top and bottom walls 100 which convergeoutwardly, burners located outside of said structure, means forsupplying` gas and air to said burners arranged to de iver an explosivemixture under pressure to said flame chambers and outlet ports 105formed substantially or approximately in the center of the side walls ofsaid ingot chamber.

11. A soaking pit for ingots comprising a. structure yof refractorymaterial having an 11o ingot chamber in combination with oppositelyextending flame chambers, burners outside the structure arranged todeliver an explosive mixture of gas and air under pressure to said flamechambers, outlet ports 115 formed in opposite walls of the ingotchambers at right angles to said flame chambers and flues communicatingwith said ports for continuously carrying off the waste gases in auni-directional path. 120

12. A soaking pit for heating ingots including non-reversible meanslocated wholly outside the pit for mixing gas and air outside the pitand burning it in the pit, and means for exhausting the waste gases from125 thehcenter of the pit in a uni-directional pat 13. A soaking pit foringots having continuously operated direct gas-fired burners on oppositesides thereof and means for con- 130 vburners located at opposite endsof said pit and ports and flues for continuously exhausting the wastegases/from the cent-er of the pit. A'

15. A soaking pit for heating ingots having direct fired 'burners atopposite ends thereof, gas and air mains connected to said burners,means for continuously forcing air required for combustion to saidburners and ducts for continuously exhausting the waste gases from thecenter of the pit.

16. A soaking pit for heating ingots having a series of direct gas firedburners connected with the gas supply pipe located outside the pit,anair main and means for continuously forcing air through said main tosaid burners and ports and iues for continuously exhausting the wastegases 'from the center of the pit.

17. An apparatus for reheating ingots prior to rolling comprising amasonry structure shaped to form a rectangular pit furnace, exteriorburners ext-ending into the opposite end walls of the furnace, gas andair mains outside the furnace connected with said burners, outlet portslocated substantially at the center of the side walls of said pit andflues connected with said ports for carrying off the waste gases in auni-directional path.

18. A soaking pit furnace having a removable top to permit insertion andremoval of ingots, burners projecting into opposite end walls of thefurnace, gas headers and air headers connected outside the furnace tosaid burners, means for carrying oft' the Waste gases including anoutlet port located in a side wall at a point between said burners.A

In witness whereof, I have hereunto signed my name.

HERBERT o. RYDING.

tinuously exhausting the waste gases from opposite sides of the centerof said soakingIr pit in a uni-directional path.

14. A soaking pit for heating ingots,

burners located at opposite ends of said pit and ports and flues forcontinuously exhausting the waste gases from the center of the pit.

15. A soaking: pit for heating ingots having direct fired burners atopposite ends thereof, gas and air mains connected to said burners,means for continuously forcing air required for combustion to saidburners and ducts for continuously exhausting the Waste gases from thecenter of the pit.

16. A soaking pit for heating ingots havingr a series of direct gasfired burners connected with the gas supply pipe located outside thepit, an air main and means for continuously forcing air through saidmain to said burners and ports and flues for continuously exhausting thewaste gases from the center of the pit.

17. An apparatus for reheating ingots prior to rolling comprising amasonry structure shaped to form a rectangular pit furnace, exteriorburners extending into the opposite end walls of the furnace, gas andair mains outside the furnace connected with said burners, outlet portslocated substantially at the center of the side walls of said pit andfines connected with said ports for carrying off the Waste gases in auni-directional path.

18. A soaking pit furnace having a Iemovable top to permit insertion andremoval of ingots, burners projecting into opposite end walls of thefurnace, gas headers and air headers connected outside the furnace tosaid burners, means for carrying off the Waste gases including an outletport located in a side wall at a point between said burners.

In witness whereof, I have hereunto signed my name.

HERBERT C. RYDING.

D so L Ai M E. R Lhasa-Herben o. Rydmg, Birmingham, lua. SOAKING PIT.Patent dated July Disclaimer filed April 16, 1932, by the patentee.

Hereby enters this disclaimer to said claim 13 of said Letters Patent.

[Qjcial Gazette Moy 10, 1932.]

